The invention relates to pharmaceutical compositions comprising a modafinil compound in solution, and in particular, to non-aqueous solutions comprising at least one organic solvent. The invention is further directed to methods of using of the compositions in the treatment of diseases.
Modafinil (C15H15NO2S), is 2-(benzhydryl-sulfinyl)acetamide, and is also known as 2-[(diphenylmethyl) sulfinyl] acetamide.
Modafinil has been described as presenting a xe2x80x9cneuropsychopharmacological spectrum characterized by the presence of excitation with hyperactivity and of hypermotility; and by the absence of stereotypy (except in high doses) and of potentialization of the effects of apomorphine and amphetaminexe2x80x9d (U.S. Pat. No. 4,177,290; hereinafter the xe2x80x9c""290 patent,xe2x80x9d which is incorporated in its entirety herein by reference). A single administration of modafinil results in increased locomotor activity in mice and increased nocturnal activity in monkeys (Duteil et al., Eur. J. Pharmacol. 180:49 (1990)). Modafinil has been successfully tested in humans for treatment of idiopathic hypersomnia and narcolepsy (Bastuji et al., Prog. Neuro-Psych. Biol. Psych. 12:695 (1988)).
Other uses of modafinil have been presented. U.S. Pat. No. 5,180,745, incorporated in its entirety herein by reference, discloses the use of modafinil for providing a neuroprotective effect in humans, and in particular for the treatment of Parkinson""s disease. The levorotatory form of modafinil, i.e.,(-)benzhydrylsulfinyl-acetamide, may have potential benefit for treatment of depression, hypersomnia and Alzheimer""s disease (U.S. Pat. No. 4,927,855, incorporated in its entirety herein by reference). European Published Application 547952 (published Jun. 23, 1993) discloses the use of modafinil as an anti-ischemic agent. European Published Application 594507 (published Apr. 27, 1994) discloses the use of modafinil to treat urinary incontinence.
Preparations of modafinil having a defined solid particle size have been described in U.S. Pat. No. 5,618,845, incorporated in its entirety herein by reference, and preparations of a levorotatory isomer of modafinil was described in U.S. Pat. No. 4,927,855. Heterocyclic derivatives of modafinil are disclosed in U.S. patent application No. 60/204,789, incorporated in its entirety herein by reference.
Modafinil has been approved for use in humans in 100 mg and 200 mg solid unit dose forms in the U.S. It is also desirable to formulate modafinil in liquid compositions. It has been observed that modafinil has very poor water and lipid solubility and it is therefore difficult to solubilize modafinil in pharmaceutically-acceptable compositions. Conventional solid and liquid formulations that include modafinil are described in the ""290 patent. Liquid suspensions or emulsions of modafinil were mentioned in U.S. Pat. No. 5,618,845. A suspension of modafinil was reported in U.S. Pat. No. 5,180,745.
It has been discovered that the solubility of a modafinil compound in pharmaceutically acceptable solvents is difficult and unpredictable. The inventors have discovered that many of the solubilizing agents were either not USP/NF listed, or they had toxicity profiles which did not allow their use at levels higher than a few tenths of a percent. The purpose of this invention is to overcome these problems and formulate a pharmaceutically acceptable composition of a modafinil compound and to provide for effective bioavailable delivery of a modafinil compound to a subject in need thereof.
Accordingly, one object of the present invention is to provide pharmaceutical compositions comprising a modafinil compound in solution. Particularly, the compositions of the present invention are non-aqueous and optionally comprise other excipients. Preferably, the compositions comprise at least one organic solvent.
It is another object of the invention to provide a method of treating a disease or disorder in a subject which comprises administering to the subject a therapeutically effective amount of the compositions of the present invention.
These and other objects, which will become apparent during the following detailed description, have been achieved by the inventors"" discovery that despite its poor solubility, a modafinil compound can be formulated as a pharmaceutical composition, wherein the modafinil compound is bioavailable upon administration to a subject in need thereof.
Thus, in a first embodiment, the present invention provides a pharmaceutical composition comprising a modafinil compound in solution. Preferably the pharmaceutical composition is non-aqueous. Preferably the pharmaceutical composition comprises modafinil.
As used herein, a xe2x80x9cpharmaceutical compositionxe2x80x9d refers to a composition that is pharmaceutically acceptable.
As used herein, the term xe2x80x9cpharmaceutically acceptablexe2x80x9d refers to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem complications commensurate with a reasonable benefit/risk ratio.
As used herein, xe2x80x9ca modafinil compoundxe2x80x9d or xe2x80x9cmodafinil compoundxe2x80x9d and the like, refers to modafinil, its racemic mixtures, individual isomers, acid addition salts, such as a metabolic acid of modafinil, benzhydrylsulfinylacetic acids, and its sulfone forms, hydroxylated forms, polymorphic forms, analogs, derivatives, cogeners and prodrugs thereof. Prodrugs are known in the art as compounds that are converted to the active agent (a modafinil compound) in the body of a subject. These and other modafinil compounds, and their preparation, have been disclosed in U.S. Pat. Nos. 4,177,290, 4,927,855, 5,719,168 and in U.S. patent application No. 60/204,789. In preferred embodiments, the modafinil compound is modafinil.
As used herein, a xe2x80x9csolutionxe2x80x9d refers to a chemically and physically homogeneous mixture of two or more substances. The solution may comprise a solid dispersed in a liquid, solid or semi-solid medium. Preferably the solution comprises a solid in a liquid medium. In more preferred embodiments, the solid that is solubilized is a particle of molecular dimensions. In context of the present application, a solution does not include inclusion complexes, such as those complexations of a drug with cyclodextrins.
As used herein, a xe2x80x9cnon-aqueousxe2x80x9d composition refers to a composition that contains from 0-10% water by weight.
As used herein, a xe2x80x9cpolyolxe2x80x9d refers to an alcohol with more than one hydroxy group. Examples include, but are not limited to glycols, such as ethylene glycol and propylene glycol, and other diols; glycerol, and other triol derivatives; and sugar alcohols.
As used herein, a xe2x80x9clower alkyl alcoholxe2x80x9d refers to a branched or straight-chained C1-C6 alkyl group containing one hydroxy group, such as ethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, pentanol, hexanol, etc; with preferred lower alkyl alcohols including ethanol, propanol and isopropanol.
As used herein, the term xe2x80x9carylalkyl alcoholxe2x80x9d refers to an aryl-substituted C1-C6 alkyl group containing one hydroxy group, such as benzyl alcohol, phenethyl alcohol, diphenylmethyl alcohol (benzhydrol), etc.; with preferred arylalkyl alcohols including benzyl alcohol, xcex1-phenethyl alcohol and xcex2-phenethyl alcohol.
As used herein, xe2x80x9ctherapeutically effective amountxe2x80x9d refers to an amount which is effective in reducing, eliminating, treating, preventing or controlling the symptoms of the herein-described diseases and conditions. The term xe2x80x9ccontrollingxe2x80x9d is intended to refer to all processes wherein there may be a slowing, interrupting, arresting, or stopping of the progression of the diseases and conditions described herein, but does not necessarily indicate a total elimination of all disease and condition symptoms, and is intended to include prophylactic treatment.
As used herein, xe2x80x9cbioavailablexe2x80x9d refers to a portion of the administered dose that is absorbed in the blood stream and can readily be determined by techniques known in the art, such as, for example, by measuring the blood serum level of a compound.
As used herein, the term xe2x80x9csubjectxe2x80x9d refers to a warm blooded animal such as a mammal, preferably a human or a human child, which is afflicted with, or has the potential to be afflicted with one or more diseases and conditions described herein.
As used herein, xe2x80x9cunit dosexe2x80x9d means a single dose which is capable of being administered to a patient, and which can be readily handled and packaged, remaining as a physically and chemically stable unit dose, comprising either a modafinil compound or a pharmaceutically acceptable composition comprising a modafinil compound.
As used herein, xe2x80x9cexcipientsxe2x80x9d refers to substances that are used in the formulation of pharmaceutical compositions, and, by themselves, generally have little or no therapeutic value. Typical excipients include antioxidants, anti-bacterial agents and other preservatives; chelating agents; buffering agents; agents for adjusting toxicity; coloring, flavoring and diluting agents; emulsifying and suspending agents; and other substances with pharmaceutical applications.
As used herein, the term xe2x80x9caboutxe2x80x9d refers to a range of values xc2x110% of a specified value. For example, the phrase xe2x80x9cabout 200xe2x80x9d includes xc2x110% of 200, or from 180 to 220.
In certain preferred embodiments, the compositions comprise a modafinil compound in any pharmaceutically acceptable solvent. The selection of a suitable solvent is one that solubilizes a modafinil compound in an amount of at least 1 mg/ml. It is understood that xe2x80x9cadequate solventxe2x80x9d, or xe2x80x9cadequate solubilityxe2x80x9d refers to a composition which gives a solubility of at least 1 mg/ml. A xe2x80x9cpoor solventxe2x80x9d or xe2x80x9cpoor solubilityxe2x80x9d refers to a composition which gives a solubility of less than 1 mg/ml.
Preferably, the solubility of modafinil is at least about 1 mg/ml. In certain embodiments, the solubility of a modafinil compound is from about 1 to about 500 mg/ml. In certain more preferred embodiments, a modafinil compound is present from about 1 to about 200 mg/ml. In other more preferred embodiments, the solubility of a modafinil compound is from about 5 to about 100 mg/ml, and in most preferred embodiments, from about 5 to about 80 mg/ml.
In certain embodiments of the invention, the compositions comprise at least one organic solvent. A suitable organic solvent can readily be determined by one skilled in the art, and is one which is pharmaceutically acceptable and imparts adequate solubility of a modafinil compound. In certain preferred embodiments, there are three solvents, and other more preferred embodiments include one or two solvents. In certain preferred embodiments, the amounts of any additional solvents comprise from about 0.5% to about 50% (v/v) of the composition, with a more preferred amount of about 1% to about 50%, and a most preferred amount about 5% to about 20% (v/v).
In certain preferred embodiments, the organic solvent is diethylene glycol monoethyl ether, propylene carbonate, dimethyl isosorbide, 1-methyl-2-pyrrolidinone (xe2x80x9cNMPxe2x80x9d), medium chain length monoglycerides, or a polyol. A highly purified diethylene glycol monoethyl ether is Transcutol(trademark). Medium chain length monoglycerides include glyceryl monocaprylate (Imwitor(copyright)), glyceryl caprylate/caprate (such as Capmul(copyright)) and polyoxyethylene glyceryl caproate (such as Labrasol(copyright)). Polyols include glycerin, propylene glycol, 1,4-butane diol, 1,3-butane diol, hexylene glycol, tetraglycol (also known as glycofuranol), or polyethyleneglycols. Preferred polyols include polyethylene glycols or xe2x80x9cPEGxe2x80x9d, which refer to a liquid or solid polymer of the general formula H(OCH2CH2)nOH, wherein n is at least 4. The preferred PEG has an average molecular weight of from about 200 to about 5000 Daltons, with a more preferred PEG from about 300 to about 2000 Daltons and a most preferred PEG from about 300 to about 1500 Daltons. Commercially available PEG materials include PEG-200, PEG-300, PEG-400, PEG-540, PEG-600, PEG-800, PEG-1000 and PEG-1450. All are commercially available from, for example, from Union Carbide Corporation in both food or pharmaceutical grades. Particularly preferred PEG solvents for use in the present composition include PEG-300, PEG-400 and PEG 1450, with PEG-300 and PEG-400 being more particularly preferred.
In other preferred embodiments, the compositions comprise additional solvents, which can be any organic solvent that adequately solubilizes a modafinil compound. Appropriate additional solvents can be readily determined by one skilled in the art and are ones which are pharmaceutically acceptable and improve the solubility of a modafinil compound. Preferably, the additional solvents comprise an organic solvent. The additional solvents may be selected from the organic solvents enunciated above, with a preferred solvent being a polyol. In certain preferred embodiments, an additional, or second solvent comprises a lower alkyl alcohol or an alkylaryl alcohol, and more preferably an alkylaryl alcohol, such as benzyl alcohol, xcex1-phenethyl alcohol or xcex2-phenethyl alcohol.
In more preferred embodiments, the solvent system includes mixtures of a polyethylene glycol and an arylalkyl alcohol. More preferred embodiments include mixtures of the preferred polyethylene glycols and arylalkyl alcohols, for example PEG-400 and benzyl alcohol, PEG-400 and xcex1-phenethyl alcohol, PEG-400 and xcex2-phenethyl alcohol, and PEG-300 and benzyl alcohol, etc. In other more preferred embodiments, the compositions comprise from about 80% to about 99% PEG-400, and from about 1% to about 20% benzyl alcohol (v/v). A further preferred embodiment, the compositions comprise from about 90% to about 99% PEG-400, and from about 1% to about 10% benzyl alcohol (v/v). In most preferred embodiments, the compositions comprise 95:5 (v/v) PEG-400:benzyl alcohol. In certain preferred embodiments, the compositions comprise a modafinil compound, or preferably, modafinil, at a concentration of about 1 to about 100 mg/ml, preferably from about 1 to about 60 mg/ml and more preferably from about 20 to about 50 mg/ml; a first organic solvent selected from glycerin, propylene glycol, diethylene glycol monoethyl ether, propylene carbonate, a medium chain length monoglyceride, dimethyl isosorbide, and a polyethyleneglycol; and a second organic solvent selected from a lower alkyl alcohol and an arylalkyl alcohol.
In certain further preferred embodiments, the first organic solvent is a polyethyleneglycol, and the second organic solvent is an alkylaryl alcohol. In more preferred embodiments, the first organic solvent is PEG-300 or PEG-400, and the arylalkyl alcohol is benzyl alcohol.
In certain preferred embodiments, the compositions comprise at least one unit dose of a modafinil compound. In certain more preferred embodiments, the compositions comprise one unit dose of a modafinil compound. Preferably, the modafinil compound is modafinil. Daily doses of modafinil preferably range from about 0.01 to 100 mg/kg of body weight. By way of general guidance, daily doses for humans range from about 0.1 mg to about 2000 mg. Preferably the unit dose range is from about 1 to about 500 mg administered one to four times a day, and even more preferably from about 10 mg to about 400 mg, administered one to two times a day. In certain preferred embodiments, the unit dose is 100 or 200 mg. In other preferred embodiments, a unit dose is one that is necessary to achieve a blood serum level of about 0.05 to about 30 xcexcg/ml, and more preferably, of about 1 to about 20 xcexcg/ml in a subject.
In a further embodiment of the present invention, there is provided a method of treating a disease or disorder in a subject, comprising administering a therapeutically effective amount of a modafinil compound, or preferably a modafinil compound, in a non-aqueous, pharmaceutical composition to a subject in need thereof. In preferred embodiments, the composition is a solution.
In certain other embodiments, the pharmaceutical compositions are useful for treatment of sleepiness, such as excessive daytime sleepiness associated with narcolepsy, or sleepiness associated with sleep apneas, tiredness, Parkinson""s disease, cerebral ischemia, stroke, sleep apneas, eating disorders, attention deficit hyperactivity disorder, cognitive dysfunction or fatigue, such as fatigue resulting from multiple sclerosis (xe2x80x9cMS fatiguexe2x80x9d); and for promotion of wakefulness, stimulation of appetite, or stimulation of weight gain.
The administration of a therapeutically effective amount of the composition can be readily determined by the attending diagnostician, as one skilled in the art, by the use of conventional techniques and by observing results obtained under analogous circumstances. In determining the therapeutically effective amount, a number of factors are considered by the attending diagnostician, including, but not limited to: the species of subject; its size, age, and general health; the specific disease involved; the degree of involvement or the severity of the disease; the response of the individual subject; the particular compound administered; the mode of administration; the bioavailability characteristic of the preparation administered; the dose regimen selected; the use of concomitant medication; and other relevant circumstances.
A therapeutically effective amount of a modafinil compound will vary depending upon a number of factors, including the dosage of the drug to be administered, the chemical characteristics (e.g., hydrophobicity) of the compounds employed, the potency of the compounds, the type of disease, the diseased state of the patient, and the route of administration. Generally, treatment is initiated with small dosages, which can then be increased by small increments until the optimum desired effect under the circumstances is achieved.
In a further embodiment, the present invention provides for pharmaceutically acceptable compositions comprising a modafinil compound, wherein upon administration of the compositions to a subject, the modafinil compound has a blood serum level of about 0.05 to about 30 xcexcg/ml in said subject. In a preferred embodiment, the modafinil compound has a blood serum level of about 1 to about 20 xcexcg/ml in said subject. In another preferred embodiment, the composition being administered to achieve the desired blood serum levels is a non-aqueous, pharmaceutical composition comprising a modafinil compound. In more preferred embodiments, the modafinil compound is modafinil.
In a further embodiment, the present invention provides for compositions that are suitable for oral administration to a subject. Oral administration includes ingestion in the form of a liquid composition, including a syrup, elixir, or emulsion; or as a capsule.
The subject compositions are contemplated to be suitable for administration in capsule form, such as hard and soft gelatin capsules and starch capsules. The hard and soft gelatin capsules are made from gelatin blends as fully discussed in The Theory and Practice of Industrial Pharmacy, 3d Ed., Lachman et al., p. 374-408 (Lea and Febiger, 1986), which is hereby incorporated by reference in its entirety. The gelatin can be blended with plasticizers, such as glycerin USP and sorbitol USP, and water. The gelatin capsules can also contain such additives as preservatives, colorants, flavorants, etc. Commercially available gelatin capsules are these made by CAPSUGEL, a division of Warner-Lambert Co., which are available in a general capsule size range of from #5 to #000 having volumes of from about 0.1 to about 1.4 ml. Furthermore, the capsules of the present compositions may be coated with an enteric coating which inhibits degradation of the capsule in the acidic environment of the stomach. Such enteric coatings are widely known in the art, such as in U.S. Pat. No. 5,206,219, the disclosure of which is incorporated herein by reference.
In certain embodiments, the compositions optionally comprise other excipients. The appropriate excipients can readily be determined by one skilled in the art, and may also include antibacterial agents, such as methyl paraben; antioxidants, such as ascorbic acid, sodium bisulfite, and fatty acid esters of ascorbic acid, such as ascorbyl palmitate; chelating agents, such as ethylene diaminetetraacetic acid; buffers, such as acetates, citrates or phosphates; agents for the adjustment of toxicity, such as sodium chloride or dextrose; flavorings; sweetening agents and coloring agents; diluents and binders; emulsifying and suspending agents; and other excipients which may be deemed useful by one skilled in the art, such as those found in The Handbook of Pharmaceutical Excipients, 2nd Ed., (The Pharmaceutical Press, London and American Pharmaceutical Association, 1994), which is hereby incorporated by reference in its entirety.
The compositions of the present invention comprise modafinil compounds, which may be readily prepared by one skilled in the art using conventional methods. Methods for preparing modafinil and various derivatives appear in U.S. Pat. No. 4,177,290, and methods for preparing other modafinil compounds appear in U.S. Pat. Nos. 4,927,855, 5,719,168 and in U.S. patent application No. 60/204,789.
There is wide latitude in formulation of the compositions of the present invention. The compositions of the present invention may be a liquid, semi-solid, or solid at room temperature. For example, higher molecular weight PEGs, such as PEG-600 are solid at room temperature, and would require heating to liquefy the PEG and to dissolve the modafinil compound. These PEG solutions may remain warm, or cooled to room temperature, as is required for the desired mode of administration. For example, an oral formulation is the form of a gelatin capsule may utilize a cooled solution of PEG-600. Whether a composition according to the invention is a liquid, semi-solid, or solid at room temperature, may depend upon the selection of components, or other concerns such as commercial viability, administration and the like.
Compositions whose inert or non-active components (i.e., components other than modafinil) are all liquid at room temperature can be prepared by simply mixing the components without heating. The desired amount of a modafinil compound can be weighed out and dissolved in the mixture of inert components, without heating. Moderate heating, preferably less than 60xc2x0 C., can be applied to hasten complete mixing of the inert components, to hasten dissolution of a modafinil compound, or both.
Preparation of compositions comprising one or more components that are solid at room temperature is carried out at a moderately elevated temperature, preferably less than 60xc2x0 C. For example, PEG-1450 at room temperature is a solid and gentle heating from between about 40 to about 60xc2x0 C. liquefies PEG-1450 for its use as a solvent. A modafinil compound can then be stirred into the heated liquid PEG solution until dissolved. Upon cooling to room temperature, the solution solidifies, and gentle warming to 40-45xc2x0 C. yields a clear solution of a modafinil compound in PEG-1450. Care must be taken to avoid excessive heating, which can lead to decomposition of one or more components of the formulation.
The materials, methods, and examples presented herein are intended to be illustrative, and not to be construed as limiting the scope or content of the invention. Unless otherwise defined, all technical and scientific terms are intended to have their art-recognized meanings.